Critical Behavior of La0.8Ca0.2Mn1−xCoxO3 Perovskite (0.1 ≤ x ≤ 0.3)

Dorra Turki (1) , Zafar Ghouri (1) , Saeed Al-Meer (1) , Khaled Elsaid (2) , Mumtaz Ahmad (1) , Ahmed Easa (1) , Gyorgy Remenyi (3) , Sami Mahmood (4) , El-Kebir Hlil (3) , Mohamed Ellouze (5) , Foued Elhalouani (5)

1 Qatar University
2 Texas A&M University at Qatar
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 JU - The University of Jordan
5 Université de Sfax - University of Sfax

The critical properties of La0.8Ca0.2Mn1−xCoxO3 (x = 0, 0.1, 0.2 and 0.3) compounds were investigated by analysis of the magnetic measurements in the vicinity of their critical temperature. Arrott plots revealed that the paramagnetic PM-ferromagnetic (FM) phase transition for the sample with x = 0 is a first order transition, while it is a second order transition for all doped compounds. The critical exponents β, γ and δ were evaluated using modified Arrott plots (MAP) and the Kouvel-Fisher method (KF). The reliability of the evaluated critical exponents was confirmed by the Widom scaling relation and the universal scaling hypothesis. The values of the critical exponents for the doped compounds were consistent with the 3D-Heisenberg model for magnetic interactions. For x = 0.1, the estimated critical components are found inconsistent with any known universality class. In addition, the local exponent n was determined from the magnetic entropy change and found to be sensitive to the magnetic field in the entire studied temperature range.

Mots clés: manganites; critical behavior; critical exponents; local exponents

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Dorra Turki, Zafar Ghouri, Saeed Al-Meer, Khaled Elsaid, Mumtaz Ahmad, et al.. Critical Behavior of La0.8Ca0.2Mn1−xCoxO3 Perovskite (0.1 ≤ x ≤ 0.3). Magnetochemistry, 2017, 3 (3), pp.28. ⟨10.3390/magnetochemistry3030028⟩. ⟨hal-02012758⟩